/Engine/Plugins/Runtime/Metasound/Source/MetasoundEditor/Public/MetasoundEditorModule.h
Primes status of MetaSound assets. Priming an asset effectively loading the asset asynchronously (if not already loaded) & registers it with the MetaSound Class Registry.
namespace Metasound { namespace Editor { enum EAssetPrimeStatus { NotRequested = 0, Requested = 1, InProgress = 2, Complete = 3, } } }